1. Check for the four categories of Site Class F requiring site-specific evaluation. If the site corresponds to any of these categories, classify the site as Site Class F and conduct a site-specific evaluation.
2. Check for the existence of a total thickness of soft clay > 10 feet (3048 mm) where a soft clay layer is defined by: su < 500 psf (24 kPa), w ≥ 40 percent and PI > 20. If these criteria are satisfied, classify the site as Site Class E.
3. Categorize the site using one of the following three methods with vs, N, and su and computed in all cases as specified.
3.1. vs, for the top 100 feet (30 480 mm) (vs method).
3.2. N for the top 100 feet (30 480 mm) ( N method).
3.3. Nch for cohesionless soil layers (PI < 20) in the top 100 feet (30 480 mm) and average, su for cohesive soil layers (PI > 20) in the top 100 feet (30 480 mm) (su method).